Exhaust gas-cooling pipe element and internal combustion engine exhaust system

Abstract

In an exhaust gas-cooling pipe element provided between an exhaust port of an internal combustion engine and an exhaust branch pipe, a center axis of an exhaust introduction opening that is connected to the exhaust port and a center axis of an exhaust discharge opening that is connected to the exhaust branch pipe are placed out of alignment with each other.

What is claimed is: 
     
       1. An internal combustion engine exhaust system comprising:
 an exhaust gas-cooling pipe element provided between an exhaust port and an exhaust branch pipe, the exhaust gas-cooling element having a plurality of exhaust channels, each of the plurality of exhaust channels has an exhaust introduction opening and an exhaust discharge opening; 
 wherein an opening portion of the exhaust port and an opening portion of the exhaust branch pipe that are connected by each of the exhaust gas-cooling channels of the exhaust gas-cooling pipe element are disposed so that the opening portion of the exhaust port is positioned above the opening portion of the exhaust branch pipe in a vertical direction, and 
 wherein a central axis of the opening of the exhaust port and a center axis of the opening of the exhaust branch pipe are non-parallel to each other, 
 wherein the exhaust gas-cooling pipe element includes a pipe wall in which a cooling fluid passageway and a communication hole are formed, the communication hole provides communication between the cooling fluid passageway and an outside, the communication hole is closed with a plug, the communication hole is provided above the cooling fluid passageway in the vertical direction, and an axis direction of the communication hole is angled to the vertical direction. 
 
     
     
       2. The internal combustion engine exhaust system according to  claim 1 , wherein the cooling fluid passageway is supplied with cooling water as a cooling fluid. 
     
     
       3. The internal combustion engine exhaust system according to  claim 2 , wherein the cooling water is cooling water for use for an internal combustion engine. 
     
     
       4. An exhaust gas-cooling pipe element provided between an exhaust port of an internal combustion engine and an exhaust branch pipe, comprising:
 a plurality of exhaust channels, each of the plurality of exhaust channels has an exhaust introduction opening and an exhaust discharge opening; 
 wherein a center axis of each of the exhaust introduction openings that are connected to the exhaust port and a center axis of each of the exhaust discharge openings that are connected to the exhaust branch pipe are placed out of alignment with each other, the center axis of each of the exhaust introduction openings and the center axis of each of the exhaust discharge openings are non-parallel to each other, 
 wherein when each of the exhaust introduction openings are connected to the exhaust port of the internal combustion engine, each of the exhaust discharge openings are below each of the exhaust introduction openings in a vertical direction, 
 wherein the exhaust gas-cooling pipe element includes a pipe wall in which a cooling fluid passageway and a communication hole are formed, the communication hole provides communication between the cooling fluid passageway and the outside, and the communication hole is closed with a plug, the communication hole is provided above the cooling fluid passageway in the vertical direction, and an axis direction of the communication hole is angled in the vertical direction. 
 
     
     
       5. The exhaust gas-cooling pipe element according to  claim 4 , wherein the cooling fluid passageway is supplied with cooling water as the cooling fluid. 
     
     
       6. The exhaust gas-cooling pipe element according to  claim 5 , wherein the cooling water is cooling water for use for the internal combustion engine. 
     
     
       7. The exhaust gas-cooling pipe element according to  claim 4 , wherein in the pipe wall of the exhaust gas-cooling pipe element, a portion of the cooling fluid passageway which is formed in a region of the pipe wall which is inclined obliquely so as to face toward an exhaust introduction opening side, the portion of the cooling fluid passageway is provided with higher heat absorption capability than another portion of the cooling fluid passageway. 
     
     
       8. The exhaust gas-cooling pipe element according to  claim 7 , wherein the portion of the cooling fluid passageway which is formed in the region is provided with higher heat absorption capability than the another portion of the cooling fluid passageway by making a capacity of the portion of the cooling fluid passageway larger than a capacity of the another portion of the cooling fluid passageway. 
     
     
       9. The exhaust gas-cooling pipe element according to  claim 7 , wherein the portion of the cooling fluid passageway which is formed in the region is provided with higher heat absorption capability than the another portion of the cooling fluid passageway by providing a difference between flow speed of a cooling fluid in the portion of the cooling fluid passageway and flow speed of the cooling fluid in the another portion of the cooling fluid passageway. 
     
     
       10. The exhaust gas-cooling pipe element according to  claim 9 , wherein the portion of the cooling fluid passageway which is formed in the region is provided with higher heat absorption capability than the another portion of the cooling fluid passageway by making the flow speed of the cooling fluid in the portion higher than the flow speed of the cooling fluid in the another portion. 
     
     
       11. An internal combustion engine exhaust system comprising the exhaust gas-cooling pipe element according to  claim 4  between the exhaust port of the internal combustion engine and the exhaust branch pipe.